The Great Train Robbery (2) - S3-E22
Revealing mistake: At the Batcave, when Batman programs the skywriter drone and switches it on, the two stunt wires are visible as it heads out of the Batcave. (00:15:40)
The Great Train Robbery (2) - S3-E22
Visible crew/equipment: When Shame has finished reading Batman's skywriting message, as he says, "Darned if I won't be there," the shadow of the boom mic dips into view at the top of the green door, at the right side of the screen. (00:17:20)
Answer: There wasn't one singular city used. It was shot in and around various locations in California, plus on a lot of sets and backlots. Ex. Some scenes were shot in LA, some in Pasadena, some in Santa Barbara, etc.
TedStixon